The specific aim of this research is to examine the relation between the physiological responses of different classes of cells within the visual system to spatial perception. It is hypothesized that one class of cells respond quickly to the global features of the stimulus, and another class responds more slowly to the stimulus detail. This hypothesis will be tested in electrophysiological and behavioral experiments in normally reared cats and in visually deprived cats with amblyopia. In the electrophysiological experiments, an instantaneous frequency analysis will be performed on responses of isolated cells to measure visual latency, response probability, response amplitude, and variability of these measures across repeated stimulus presentations. In the behavioral experiments, a reflex modification procedure will be used to quickly measure spatial sensitivity and visual latency. These experiments will provide some insight into the physiological bases of human amblyopia. Human amblyopes have a reduced spatial sensitivity and abnormally long perception times, which reflect both a delay and disrupton in the normal order of processing of spatial information. The experiments proposed here are designed to study the physiological bases of these deficits.